diff --git a/src/DataTables/Column/EnumColumn.php b/src/DataTables/Column/EnumColumn.php
index 1f591108..04813db9 100644
--- a/src/DataTables/Column/EnumColumn.php
+++ b/src/DataTables/Column/EnumColumn.php
@@ -43,7 +43,7 @@ class EnumColumn extends AbstractColumn
         return ($this->getEnumClass())::from($value);
     }
 
-    protected function configureOptions(OptionsResolver $resolver)
+    protected function configureOptions(OptionsResolver $resolver): static
     {
         parent::configureOptions($resolver);
 
diff --git a/src/DataTables/LogDataTable.php b/src/DataTables/LogDataTable.php
index 87317f40..d36f819a 100644
--- a/src/DataTables/LogDataTable.php
+++ b/src/DataTables/LogDataTable.php
@@ -139,7 +139,7 @@ class LogDataTable implements DataTableTypeInterface
                 if ($context instanceof PartStockChangedLogEntry) {
                     $text .= sprintf(
                         ' (<i>%s</i>)',
-                        $this->translator->trans('log.part_stock_changed.' . $context->getInstockChangeType())
+                        $this->translator->trans('log.part_stock_changed.' . $context->getInstockChangeType()->toExtraShortType())
                     );
                 }
 
diff --git a/src/Entity/LogSystem/PartStockChangeType.php b/src/Entity/LogSystem/PartStockChangeType.php
new file mode 100644
index 00000000..bbd574a7
--- /dev/null
+++ b/src/Entity/LogSystem/PartStockChangeType.php
@@ -0,0 +1,51 @@
+<?php
+/*
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ *  Copyright (C) 2019 - 2023 Jan Böhmer (https://github.com/jbtronics)
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as published
+ *  by the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace App\Entity\LogSystem;
+
+enum PartStockChangeType: string
+{
+    case ADD = "add";
+    case WITHDRAW = "withdraw";
+    case MOVE = "move";
+
+    /**
+     * Converts the type to a short representation usable in the extra field of the log entry.
+     * @return string
+     */
+    public function toExtraShortType(): string
+    {
+        return match ($this) {
+            self::ADD => 'a',
+            self::WITHDRAW => 'w',
+            self::MOVE => 'm',
+        };
+    }
+
+    public static function fromExtraShortType(string $value): self
+    {
+        return match ($value) {
+            'a' => self::ADD,
+            'w' => self::WITHDRAW,
+            'm' => self::MOVE,
+            default => throw new \InvalidArgumentException("Invalid short type: $value"),
+        };
+    }
+}
\ No newline at end of file
diff --git a/src/Entity/LogSystem/PartStockChangedLogEntry.php b/src/Entity/LogSystem/PartStockChangedLogEntry.php
index 34ae15fb..6c56bb48 100644
--- a/src/Entity/LogSystem/PartStockChangedLogEntry.php
+++ b/src/Entity/LogSystem/PartStockChangedLogEntry.php
@@ -38,7 +38,7 @@ class PartStockChangedLogEntry extends AbstractLogEntry
 
     /**
      * Creates a new part stock changed log entry.
-     * @param  string  $type The type of the log entry. One of the TYPE_* constants.
+     * @param  PartStockChangeType $type The type of the log entry.
      * @param  PartLot  $lot The part lot which has been changed.
      * @param  float  $old_stock The old stock of the lot.
      * @param  float  $new_stock The new stock of the lot.
@@ -46,14 +46,10 @@ class PartStockChangedLogEntry extends AbstractLogEntry
      * @param  string  $comment The comment associated with the change.
      * @param  PartLot|null  $move_to_target The target lot if the type is TYPE_MOVE.
      */
-    protected function __construct(string $type, PartLot $lot, float $old_stock, float $new_stock, float $new_total_part_instock, string $comment, ?PartLot $move_to_target = null)
+    protected function __construct(PartStockChangeType $type, PartLot $lot, float $old_stock, float $new_stock, float $new_total_part_instock, string $comment, ?PartLot $move_to_target = null)
     {
         parent::__construct();
 
-        if (!in_array($type, [self::TYPE_ADD, self::TYPE_WITHDRAW, self::TYPE_MOVE], true)) {
-            throw new \InvalidArgumentException('Invalid type for PartStockChangedLogEntry!');
-        }
-
         //Same as every other element change log entry
         $this->level = LogLevel::INFO;
 
@@ -61,7 +57,7 @@ class PartStockChangedLogEntry extends AbstractLogEntry
 
         $this->typeString = 'part_stock_changed';
         $this->extra = array_merge($this->extra, [
-            't' => $this->typeToShortType($type),
+            't' => $type->toExtraShortType(),
             'o' => $old_stock,
             'n' => $new_stock,
             'p' => $new_total_part_instock,
@@ -71,7 +67,7 @@ class PartStockChangedLogEntry extends AbstractLogEntry
         }
 
         if ($move_to_target instanceof PartLot) {
-            if ($type !== self::TYPE_MOVE) {
+            if ($type !== PartStockChangeType::MOVE) {
                 throw new \InvalidArgumentException('The move_to_target parameter can only be set if the type is "move"!');
             }
 
@@ -90,7 +86,7 @@ class PartStockChangedLogEntry extends AbstractLogEntry
      */
     public static function add(PartLot $lot, float $old_stock, float $new_stock, float $new_total_part_instock, string $comment): self
     {
-        return new self(self::TYPE_ADD, $lot, $old_stock, $new_stock, $new_total_part_instock, $comment);
+        return new self(PartStockChangeType::ADD, $lot, $old_stock, $new_stock, $new_total_part_instock, $comment);
     }
 
     /**
@@ -104,7 +100,7 @@ class PartStockChangedLogEntry extends AbstractLogEntry
      */
     public static function withdraw(PartLot $lot, float $old_stock, float $new_stock, float $new_total_part_instock, string $comment): self
     {
-        return new self(self::TYPE_WITHDRAW, $lot, $old_stock, $new_stock, $new_total_part_instock, $comment);
+        return new self(PartStockChangeType::WITHDRAW, $lot, $old_stock, $new_stock, $new_total_part_instock, $comment);
     }
 
     /**
@@ -118,16 +114,16 @@ class PartStockChangedLogEntry extends AbstractLogEntry
      */
     public static function move(PartLot $lot, float $old_stock, float $new_stock, float $new_total_part_instock, string $comment, PartLot $move_to_target): self
     {
-        return new self(self::TYPE_MOVE, $lot, $old_stock, $new_stock, $new_total_part_instock, $comment, $move_to_target);
+        return new self(PartStockChangeType::MOVE, $lot, $old_stock, $new_stock, $new_total_part_instock, $comment, $move_to_target);
     }
 
     /**
      * Returns the instock change type of this entry
-     * @return string One of the TYPE_* constants.
+     * @return PartStockChangeType
      */
-    public function getInstockChangeType(): string
+    public function getInstockChangeType(): PartStockChangeType
     {
-        return $this->shortTypeToType($this->extra['t']);
+        return PartStockChangeType::fromExtraShortType($this->extra['t']);
     }
 
     /**
@@ -177,30 +173,4 @@ class PartStockChangedLogEntry extends AbstractLogEntry
     {
         return $this->extra['m'] ?? null;
     }
-
-    /**
-     * Converts the human-readable type (TYPE_* consts) to the version stored in DB
-     */
-    protected function typeToShortType(string $type): string
-    {
-        return match ($type) {
-            self::TYPE_ADD => 'a',
-            self::TYPE_WITHDRAW => 'w',
-            self::TYPE_MOVE => 'm',
-            default => throw new \InvalidArgumentException('Invalid type: '.$type),
-        };
-    }
-
-    /**
-     * Converts the short type stored in DB to the human-readable type (TYPE_* consts).
-     */
-    protected function shortTypeToType(string $short_type): string
-    {
-        return match ($short_type) {
-            'a' => self::TYPE_ADD,
-            'w' => self::TYPE_WITHDRAW,
-            'm' => self::TYPE_MOVE,
-            default => throw new \InvalidArgumentException('Invalid short type: '.$short_type),
-        };
-    }
 }
diff --git a/src/Services/LogSystem/LogEntryExtraFormatter.php b/src/Services/LogSystem/LogEntryExtraFormatter.php
index 6ace35e8..5852265f 100644
--- a/src/Services/LogSystem/LogEntryExtraFormatter.php
+++ b/src/Services/LogSystem/LogEntryExtraFormatter.php
@@ -33,6 +33,7 @@ use App\Entity\LogSystem\ElementEditedLogEntry;
 use App\Entity\LogSystem\ExceptionLogEntry;
 use App\Entity\LogSystem\LegacyInstockChangedLogEntry;
 use App\Entity\LogSystem\PartStockChangedLogEntry;
+use App\Entity\LogSystem\PartStockChangeType;
 use App\Entity\LogSystem\SecurityEventLogEntry;
 use App\Entity\LogSystem\UserLoginLogEntry;
 use App\Entity\LogSystem\UserLogoutLogEntry;
@@ -187,7 +188,7 @@ class LogEntryExtraFormatter
             if ($context->getComment() !== '') {
                 $array['log.part_stock_changed.comment'] = htmlspecialchars($context->getComment());
             }
-            if ($context->getInstockChangeType() === PartStockChangedLogEntry::TYPE_MOVE) {
+            if ($context->getInstockChangeType() === PartStockChangeType::MOVE) {
                 $array['log.part_stock_changed.move_target'] =
                     htmlspecialchars($this->elementTypeNameGenerator->getLocalizedTypeLabel(PartLot::class))
                     .' ' . $context->getMoveToTargetID();